Following the very successful ESA Swarm mission, the NanoMagSat project aims to deploy and operate a new LEO constellation consisting of a baseline of three identical 16U nanosatellites to further monitor the magnetic field from space, as well as the ionospheric environment. The foreseen payload is a mix of instruments with flight heritage (multi-Needle Langmuir Probe) and new magnetometers either derived from the Swarm Absolute Scalar Magnetometer (Miniaturized Absolute Magnetometer) or specifically designed for NanoMagSat to extend the measurement capabilities towards space weather related issues (High Frequency Magnetometer). This paper will report on the progress achieved within a Risk Retirement Activity framework funded by ESA in the context of its Scout program to address the main challenges of this mission. These can be grouped into three categories: - Payload related issues, i.e., magnetometers development and qualification, as well as design of an ultra-stable optical bench on which both the MAM and the Star Trackers will be co-mounted - Design of a 3m deployable boom to minimize the residual stray fields generated by the satellite platform at the magnetometers location. In folded configuration, this boom shall fit into a 2U volume. It also has to overcome the stiffness of the harnesses connecting the instruments to the platform to ensure proper deployment. Last but not least, given its proximity to the magnetometers, the boom shall also be strictly amagnetic. This implies significant constraints on the choice of materials used. - Satellite platform subsystems accommodation and reduction of their magnetic signatures. Fitting all the hardware into the allocated volume is in itself a challenge. In addition, although the functions provided by the platform are quite generic, special care has to be taken to meet the mission's accuracy requirements. This implies a redesign of the power storage and of the distribution boards, to very significantly improve the overall magnetic budget. Results obtained during dedicated tests on representative engineering models will be compared to the mission's performance requirements. Remaining work towards mission implementation will also be detailed.